In the copending patent application, Ser. No. 650,297, of Richard L. Wilson, filed Jan. 19, 1976, and assigned to the assignee of the present application, there is shown and described a graduated release type brake control valve device that is operated by a reduction in brake pipe pressure on one side of a movable abutment relative to control reservoir pressure on the other side wherein the abutment embodies therein a control reservoir charging valve mechanism, a filter and a choke arranged in series. This charging valve mechanism comprises a two-position valve that, while in one position, enables the flow of fluid under pressure from a train brake pipe to a control reservoir thereby providing for the charging of this reservoir to the pressure carried in the train brake pipe, and, upon movement to the other position in response to a reduction of pressure in the train brake pipe, closes this charging communication thereby enabling the trapped pressure in the control reservoir to operate this brake control valve device to effect graduated brake applications and releases in accordance with variations of the pressure in the train brake pipe.
Since the rolling stock of most railroads comprise some vehicles that require a graduated release type brake control valve device to provide the proper braking for the type of service in which these vehicles are used, and other vehicles that require a direct release type brake control valve device to provide the proper braking for the type of service in which these other vehicles are used, it is apparent that it would be most desirable to provide a railway vehicle brake control valve device with a change-over means whereby this brake control valve device may be selectively conditioned for either graduated release operation or direct release operation.
Accordingly, it is the general purpose of the present invention to provide a railway vehicle brake control apparatus that embodies a brake control valve device that may be selectively conditioned to operate either in the manner of a graduated release type brake control valve device, or in the manner of a direct release type brake control valve device.